Figure 1.

Dependence of the dark resting potential and light-evoked responses of a retinal horizontal cell of the salamander to alterations in extracellular H⁺. Modified from Kleinschmidt (1991). An intracellular sharp electrode was used to monitor membrane potential in a single horizontal cell impaled in an isolated retinal preparation superfused with the pH of the solution buffered with 20 mM HEPES. Alternating red (600 nm) and green (555 nm) 100 ms full field flashes, separated by 3 s and adjusted to give equal cone responses were used to stimulate the cell. The author notes that the responses to the different lights can be distinguished by the small rod-driven tails found only in responses to green stimuli.